-You've given us a wonderful Chinese dinner, Mrs. Wang.

-- ______. 

A．Oh, I'm afraid I didn't cook very well

B．I' m glad you enjoyed it

C．Come again when you are free

D．It's not necessary for you to say so

患者，男，36岁。网络工程师。2个月来学习太极拳，2周前无意中发现左腘窝部无痛性肿块，无其他不适。

首先应考虑的诊断为（）

A.脂肪瘤

B.腘腘窝半月板囊肿

C.腘窝囊肿

D.腘窝纤维瘤

E.腘窝骨软骨瘤